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  1. OMG Issue

BPMN21 — Outgoing Paths after Inclusive Gateway

  • Key: BPMN21-257
  • Legacy Issue Number: 15808
  • Status: open  
  • Source: scch.at ( Christine Natschlär)
  • Summary:

    I think that the number of outgoing paths after an Inclusive Gateway are conflicting. According to page 37 and page 300, all combinations of paths MAY be taken, from zero to all. However, on page 362 it is mentioned several times that one or more alternative branches are chosen (one of more
    branches MAY be activated upstream). The difference is taking zero paths.

    Is it possible to take zero paths after an Inclusive Gateway? If yes, is the process flow interrupted or can the flow just continue after a later merge? What happens if there is no corresponding merge for the split? It seems that taking zero paths is possible based on the conditions which are evaluated separately.

    However, I think, that the specification from page 362 should be taken and that one or more outgoing paths receive a token. Then A OR B can also be transformed to (A XOR B) XOR (A AND B). Also the definition of logical disjunction is that one or more of its operands are true (according to the truth table A OR B is only false if A is false and B is false).

    If the intention behind taking zero paths is that it should be possible to execute non of the tasks, then my second suggestion would be to define that an "empty" path is mandatory and if no task should be executed then a token can be sent on the "empty" path.

    Also if the separately evaluated conditions are the reason for allowing zero paths, again a mandataroy empty default path could be a solution to avoid that the inclusive split contradicts with the logical disjunction.

    As Inclusive Gateways are a very complex topic a discussion would be interesting.

  • Reported: BPMN 2.0 — Tue, 9 Nov 2010 05:00 GMT
  • Updated: Fri, 6 Mar 2015 20:57 GMT